Device for cooling a heat generator by means of a circulating auxiliary liquid



July 16, 1935. NESSELMANN 2,008,333

DEVICE FOR COOLING A HEAT GENERATOR BY MEANS OF A CIRCULATING AUXILIARYLIQUID Filed June 22, 1932 r j? 1/ 5 C lf j i 4 M WM ' 25 its boilingpoint, whereas at temperatures above closes the valve II. It designatesthe electrical 25 Patented July 16, i935 i i UNITED STATES PATENT OFFICEDEVICE FOR CGOLING A HEAT GENERATOR IIiIYQMEANS OF A CIRCULA'IINGAUBLIABY Kurt Nesselmann, Berlin- Siemensstadt, Germany, assignor toSiemens-Schuckertwerke Aktiengesellschaft, Berlin-Siemensstadt, Germany,a corporation of Germany Application June 22, 1932, Serial No. 618,675In Germany June 30, 1931 10 Claims. (Cl. 62 -118) My invention relatesto a device for cooling a peri a s rpti n r fl' ti pp r heatgenerator bymeans of a circulating auxwhich operates With Solid absorptionedifliliary liquid, and more particularly to a device Referring to thedrawing, the reference char- 'for periodic absorption refrigeratingapparatus. acter I denotes the generator-absorber contain- Devices forthe transfer of heat which operate ing a solid absorbent consisting, forinstance, of

with an auxiliary liquid circulating between a calcium chloridesaturated with ammonia. From heat generator and the heat consumer areknown the generator-absorber the refrigerating meto those skilled in theart. Thus, for instance, dium passes during the generating periodthrough it is common practice both for heating and coola conduit 2 intoan air-cooled condenser 3 and ing purposes to transfer the heat by meansof thence into a containerl communicating with an 10 a circulatingauxiliary medium which remains evaporation coil 5 projecting into thecooling liquid during the entire process. Analogously, an chamber 6, thecoil 5 being placed in a receptacle auxiliary liquid may also beemployed for the I! containing asalt solution. The generator-ababovepurpose, the circulation of which is efsorber is surrounded by a coolingjacket I from 5 fected by the alternate evaporation and conthe upperpart of which a conduit 8 extends densation of the liquid. to anair-cooled return cooler 9, whereas a con- My invention contemplates adevice for the duit l0 connects the return cooler to the lower transferof heat with an auxiliary liquid cirend of the cooling jacket I. A valvell serves to culating between the heat generator and the interrupt thecirculation of the auxiliary liquid heat consumer, and its object is toprovide two during the generating period, the valve being con- 20circulating paths for the auxiliary liquid which trolled in such amanner as to be open during are so arranged in relation to each otherthat the the absorption period and closed during the genauxiliary liquidcan only circulate in the one circrating period. The control is effectedby means culating path at temperatures which lie below of anelectromagnet 20 which, when energized,

the boiling point a circulation may also take place heating element forthe generator-absorber ",l in the other circulating path by thealternate During the generating period the heating elementevaporationand condensation of the liquid. In is switched in at the same time withthe electroeffecting such a transfer of heat, the heat conmagnet 20 by acontact making clock ll. Dursumer designed as a cooler for the auxiliarying the absorption period the contact making 30 liquid may be carriedout so as not to be comclock breaks in a well-known manner the circuit Py fi d w e auxiliary liquid- In h for the heating element ill and theelectromagnet case a conduit leads from the heat generator to Ill. I2 isa cooler which acts at th same m the cooler below the surface of theliquid cona an expansion vessel for the auxiliary liquid tained thereinand another conduit above the n is provided at the top with an inletconnec- 35 same, whereas a common conduit returns to the ti I: hich, ifdesired, may be designed as a heat e r t rsafety valve. The expansionvessel l2 takes up The dev e accord to t e inve t on may be theincreased volume of the cooling liquid durused for a ious practical purpses. It is paring the heating so as to prevent an undue in 40 ticularlysuitable as safety device against undue crease inv pressure in thesystem. A conduit I6 40 r ses n te e in t e e era o In case connects theexpansion vessel I! with the return the-circulation of liquid should beinterrupted in cooler 9, A conduit l4 extending from the uppe/ theconduit entering at a point below the level part of th cooling jacket Ienters the expansilil i 0f the q d; o instance, y ing a cook or vesselI! at a point above the highest possible valve, the temperature in thegenerator may 1 1 of t 1iqu1d rise within unreasonable limits. In thiscase the As heat carrier an auxiliary liquid i employed conduit enteringthe cooler above the surface thi apparatus, the boiling point of whichis of the liquld and by-passing the Valve Prevents so high that normallyno evaporation of the coolthe temperature in the generator from obtainimedium may take place. Turpentine oil and ing too high a value, since inthis case the cirtransformer oil are, for instance, suitable for this 50culation of the liquid is introduced by the alterpurpose. Liquidmixtures or solutions may also nate evaporation and condensation of theliquid. be employed. The space in the expansion vessel The accompanyingdrawing represents an em- I2 above the surface of the liquid ispreferably bodiment in a diagrammatic form of a device fllled with aninert gas, for instance nitrogen, in

'55 for carrying off the heat of absorption of a order to avoid adecomposition of the liquid.

Under normal working conditions the auxiliary liquid contained in thegenerator cooling jacket I is heated during the absorption period by theheat of absorption so that the liquid rises through the conduit 8 intothe return cooler 9, and there the liquid gives off the heat to theatmosphere with the aid of radiating ribs. The cooled-ofi liquid returnsthen from the return cooler 9 through the conduit ID to the lower partof the cooling jacket 1. During the generating period the automaticcirculation must be interrupted in order not to carry off unnecessarilythe heat to the atmosphere. To this end, the valve II is closed in theabove described manner. Since the generator I2 is electrically heatedand the valve I I is electromagnetically controlled in accordance withthe contact making clock I9, it may happen that owing to a failure ofthe contact making clock, the generator-absorber I continues beingheated and that the valve I I remains closed. In this manner such hightemperatures may prevail in the generator as to give rise .to abreakdown of the apparatus. In the apparatus according to the inventionthis drawback is avoided, for as a result of the higher temperatureprevailing in the generator the normally liquid cooling agents of thecirculating system begins now to evaporate in the generator coolingjacket I. The cooling medium rises in the conduit I4 by means of vaporbubbles and passes along with the latter into the expansion vessel I2where the vapor is condensed. To accelerate the condensation it ispreferable to provide the expansion vessel with radiating fins l5. Owingto the thermo-siphon action of the vapor bubbles in the conduit I4 acirculation of the cooling medium is efiected from the cooling jacket 'Ithrough the conduit I4, the expansion vessel I2, the connecting conduitI6, the return cooler 9 and through the conduit I0 back to the coolingjacket I so that the excess heat from the expansion vessel I 2 and thereturn cooler 9 is given off to the atmosphere.

I claim as my invention:

1. In a device for cooling a heat generator, a circulating systemcomprising a part in heat exchange relation with the heat'generator, aheat consuming device and conduits therefor, a liquid in saidcirculating system having a boiling point higher than the maximumtemperature prevailing under normal operatingconditions, and a safetydevice connected with said circulating system operable as a result ofthe boiling of the liquid upon undue rises in temperature of the heatgenerator.

2. In a device for cooling a heat generator, a circulating systemcomprising a part in heat exchange relation with the heat generator, acooling medium in said circulating system having a boiling point higherthan the maximum temperature prevailing under normal operatingconditions, means for interrupting the circulation in said system, andmeans for insuring a suflicient amount of circulation of the coolingmedium during said interruption to maintain the temperature at a safetypoint and prevent undue rises of said tem- I perature.

3. In a device for cooling a heat generator, a circulating systemcomprising a part in heat exchange relation with the heat generator, abranch circuit communicating with said system, and a cooling mediumhaving a boilng point such that said medium circulates as a liquid insaid system under normal operating conditions and vaporizes into thebranch circuit under abnormal operating conditions whereby to preventundue rises in tem-' perature of the heat generator.

4. In a device for cooling a heat generator, a circulating systemcomprising a part in heat exchange relation with the heat generator, acooling medium for circulating in said system, means in said circulatingsystem for interrupting the flow of the cooling medium during heatingoperation of the generator and normal temperature operations thereof,and means for by-passing said medium about said interrupting means whenundue rises intemperature of the heat generator occur.

5. A device for cooling a heat generator, comprising a circulatingsystem having a part in heat exchange relation with the heat generatorand a by-pass conduit communicating therewith to form two circulatingpaths, and an auxiliary liquid adapted to circulate in one of said pathsat temperatures in the heat generator below the boiling point of saidliquid and to circulate in the other path incident to,vaporization ofsaid fluid at temperatures prevailing in the heat generator above theboiling point of said liquid.

6. A device for cooling a heat generator, comprising a circulatingsystem having a part in heat exchange relation with the heat generatorand a by-pass conduit communicating therewith to form two circulatingpaths, an auxiliary liquid adapted to circulate in one of said paths attemperatures in the heat generator below the boiling point of saidliquid and to circulate in the other path incident to vaporization ofsaid liquid at temperatures prevailing in the heat generator above theboiling point of said liquid, and a cooling means in said by-passconduit for cooling the liquid under the last mentioned conditions.

7. In a device of the class described the combination of a heatgenerator, a liquid container surrounding the generator, a coolingliquid in said container, a liquid cooler, conduits connecting thecooler with the container to form a liquid circulating system, a valvein said system for interrupting the circulation, and a safety means forreceiving a part of the cooling medium comprising an expansion chamberconnected to said system and adapted to relieve the system of excesspressure when undue temperature occurs in the generator during theinterruption of the circulation.

8. A device as claimed in claim 7 wherein the expansion chambercomprises a condenser and said condenser is connected to the circulatingsystem by a rising pipe in which the vapors from the liquid raise saidliquid to the condenser for condensation and return to the said system.

9. Ina device for cooling a heat-generator, a circulation systemcomprising a part in heat exchange relation with the generator, acirculating medium in said system partly filling the same, cooling mansfor cooling the circulating medium, two conduits between said coolingmeans and the part in heat exchange relation with the generator arrangedto convey the circulating medium from the part in heat exchange with thegenerator to the cooler,,one of the said conduits being connected withthe cooling means at a point above the surface of the circulating mediumand the other connected at a point below the level of the medium, and aconduit arranged to convey the circulating medium from the cooler backto the part in heat exchange with the generator.

10. In a device for cooling a heat generator, a circulating systemcomprising a Part in heat exchange relation with the generator, acirculating the part in heat exchange with the generator to the cooler,one of said conduits being connected with the cooling means at a pointabove the surface of the circulating medium and the other connected at apoint below the level of the medium, and a conduit arranged to conveythe circulating medium from the cooler back to the part in heat exchangewith the generator.

KURT NESSELMANN.

